Plywood Grade Stamp

APA Grade Stamp

Reading Plywood and OSB Grade Stamps (back of panel)

The span rating indicates the maximum inches between supports that the panel may be applied. If there are two numbers, the first refers to roof applications, the second to floor applications.

The exposure durability classification defines whether the panel should be used for interior or exterior applications:

  • Exterior panels have a fully waterproof bond and are designed for applications subject to permanent exposure to the weather or moisture.
  • Exposure 1 panels are designed for protected construction and industrial applications and can be exposed to the elements for a short time, but not permanently.
  • Exposure 2 panels are intended for protected construction and industrial applications where the potential for conditions of high humidity and water leakage exist.
  • Interior panels are manufactured with an interior grade glue and are intended for interior applications only.

The thickness of the panel is also included on the stamp. Plywood is sized 1/32" under its called size. Hence, 1/2" plywood measures 15/32".

Special thanks to Georgia Pacific for input to this page.

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